1. Field of the Invention
The present invention relates generally to hermetically sealing electronic elements associated with electronic circuitry. More particularly, the present invention relates to providing hermetically sealed packages of flexprints and chips, integrated circuits, and other electronic elements.
2. Description of Related Art
Flexprint electronic blanket packages are widely used to house and interconnect electronic elements including integrated circuit chips. The flexprint package generally includes a support wafer or base onto which the flexprint blanket is placed. The flexprint blanket or body is made up of one or more layers of flexprint. Flexprint is the term commonly used to describe flexible layers of plastic which are laminated with alternating layers of a metal and having an outer metal coating. The most common flexprints are made from polyimide laminated with copper.
The plurality of layers of flexprint which form the blanket package are laminated onto the underlying silicon wafer. Usually between 5 and 15 flexprint layers are used to form the blanket body which generally is on the order of 0.050 inch (0.12 cm) thick. Openings or cavities are made in the blanket body for housing various electronic integrated circuits (IC's) and other elements. The silicon wafer forms the bottom of the well with the electronic element typically being attached to the silicon wafer by eutectic bonding. Electrical connections are made between the chip and the various metallic pads present on the flexprint layers.
A typical problem with any electronic package is the prevention of contamination or corrosion of the integrated circuit chips and electrical connections. In order to avoid premature failure of the electronics package, it is important that the package assembly be hermetically sealed to prevent such corrosion and contamination of the integrated circuit. Accordingly, there is a continuing need to provide flexprint blanket and other flexprint assemblies wherein the cavities in which the electronic elements are located are hermetically sealed. Preferably, the hermetic sealing of the cavities is achieved quickly, simply and efficiently, at a minimum of cost. Although adequate hermetic seals may be obtained utilizing a variety of metallically sealed packages, there is still a continuing need to simplify and reduce the cost, weight and volume of electronic assemblies.
The dissipation of heat from electronic package assemblies is also an important consideration. Without adequate cooling systems, the electronic package will quickly overheat and destroy or shorten the life of the temperature sensitive electronic elements contained therein. This problem is especially critical in devices which operate at power levels of 50 watts and beyond. There is a continuing need to provide systems and methods which efficiently cool and transfer the generated heat away from IC's, to prevent overheating.